Tamper evident closures are important in a number of areas, particularly in the food industry. While the concept of the tamper evident closure is a good one in providing the consumer some assurance that the contents of the container being purchased have not been altered after packaging, the tamper evident feature can also introduce packaging problems.
For example, in the field of spice containers, multiple door closures are sometimes used. A common type of container for spices is a rectangular can, historically metal, but now also sometimes plastic, which has a rigid plastic server lid affixed to the open end of the can. The server lid includes dispensing ports covered by flaps which are typically hinged to the base of the lid. Typically the lid has multiple flaps covering the various dispensing ports. The dispensing ports may be in the form of sift holes for sprinkling the spice, a pour hole for pouring spice out of the container or a spoon hole for spooning a measured amount out of the container, or any combination thereof.
When placing multiple flaps on a container having a lid of limited dimension, the further inclusion of a tamper evident feature sometimes requires compromises which are not acceptable in all cases. For example, Gray, U.S. Pat. No. 6,422,411, assigned to the assignee of the present invention, describes a tamper evident overcap for a multiple flap spice container. The overcap approach is useful in that it does not require a reduction in the size of the ports or flaps on the cover. However, the complication it introduces is the need to mold an additional piece, the overcap, and to assemble the overcap to the server lid.
Foster, U.S. Pat. No. 4,621,744, also assigned to the assignee of the present invention, shows another approach. As with the typical multiple flap spice closure, the device described in the Foster patent can be molded as a single unit. However, in order to achieve the tamper evident feature, the tear strip in Foster uses valuable “real estate” on the closure and requires a reduction in size of the ports and the flaps which cover them. In addition, since the tear strip and the flaps with which it is associated are more or less coplanar on top of the closure, removing of the tear strip, by tearing it upwards, has a tendency to also attempt to open the flaps. This is undesirable to some users.
An additional significant issue raised by the closure in the Foster patent, and others like it, is the requirement on the spice lid manufacturer to prepare a new set of molds to include the tamper evident feature. As will be known to those skilled in this art, the multiple cavity molds which are used to make closures such as these are extremely expensive, highly engineered units. In addition, the lead time for securing molds is often significant. If one were to have the basic three-flap design of the Foster patent in a non-tamper evident configuration, in order to add tamper evidency as shown in the Foster patent would require a redesign of the mold to reconfigure the ports, the flaps and the basic cover configuration. The old existing molds would not be usable, and a completely new set of molds would be required to add the tamper evidency feature.